Topics In This Section
1. Introduction
2. General Rules of Frying
3. Temperature Control
4. Preparation of Food
5. Fat Absorption and Topping Up
6. Choice of Frying Medium
7. The Spoilage of Fats and Oils
8. Cleaning
9. Frying Specific Foods
10. Recommended Frying Temperatures
11. The Basic Chemistry of Fats and Oils
12. The Chemistry of Fat Spoilage
13. The Visible Effects of Chemical Spoilage
14. The Role of the Oil Refiner
15. The Role of the Fryer
16. Fire Hazards
Reproduced with permission from Pura Food Products Limited
6. Choice of Frying Medium
Due to the nature of their composition, some oils and fats tend to be more sensitive to heat and spoil more rapidly, than others. It is therefore safer to
use the fats and oils which have been specifically designed and processed for the purpose of frying.
There is a wide range of frying media on the market, and the ones which are available can be divided into three groups, depending on their appearance at room
temperature:-
Solid frying fats are generally very stable if they have been refined and stored properly. An exception is unrefined dripping which is more sensitive to
heat and which is generally used at frying temperatures which are lower than normal.
Solid frying fats have to be dug out of the carton and the correct procedure is to melt them out gently (at temperatures not exceeding 132C (270F) before
heating to frying temperature. Otherwise, they might burn before they melt. Many operators ignore this precaution, and frying life can be reduced as a result,
despite the intrinsic stability of the material.
Liquid oils are easier to handle and use because they can be poured. The most stable liquid oils - groundnut and corn oils, for example - are generally the
most expensive. Other oils and blends of oils are more economical, but rather less stable chemically.
Fluid frying media can offer the best of both worlds. They are pourable and do not need special melting before heating to frying temperature. They are stable,
and generally more stable than normal vegetable oil blends. This improved stability, and the longer frying life which this entails, is brought about by additional
processing during the production of the frying medium.
Price, stability and flavour (lack of off-flavour) are other considerations when choosing an oil. Frying media often contain other materials, the most important
being antioxidants and antifoaming agents or silicones. Antioxidants improve the storage life by suppressing spoilage by oxidation, and antifoaming agents extend frying
life in batch fryers by controlling foaming.
It is useful to choose the frying medium to fit the food being fried and the busy-ness of the frying cycle. It has already been mentioned that regular topping up
can damp down the rate of spoilage. If the food has a very low rate of fat absorption, or if the frying process is not busy, it is a definite advantage to choose
from the most stable media. If the food has a high rate of absorption, fat spoilage is more likely to be controlled by continuous topping up with fresh fat or oil.
In this case there may be less need to use a long-life frying medium.